1. Field of the Invention
The present invention relates to the field of image capture. Specifically, the present invention relates to a compact portable apparatus and system for scanning and correspondingly capturing images electronically.
2. Related Art
Modern portable image capturing devices enable users to capture information, such as lines or pages of printed text, snapshot photographs, or video, in an electronic form. Information contained in printed media may be captured electronically by scanning type image capture devices. These portably mimic the functionality of larger, more cumbersome desk-top type or other scanner designs, built for office like environments. Scenic information, on the other hand, may be captured electronically by portable digital cameras and/or video recording cameras. At the heart of such image capturing systems is the charged-coupled device (CCD), or smaller, less expensive variants, such as the contact image sensor (CIS).
Printed information is captured by scanning lines of text with the image capturing device and storing the information within the device, or in an auxiliary storage mechanism, such as a flash memory device, for later retrieval by the user. Retrieval may be by viewing the information directly on a display integral to the image capturing device. Portable digital cameras generally record scenic information in formats such as graphics interchange format (GIF) and Joint Photographic Expert Group (JPEG) electronic files. Video cameras generally record in a video format such as digital television (DTV) and Joint Motion Picture Expert Group (MPEG) digital files, and National Television Standards Committee (NTSC) analog signals.
In an image capturing device with instant, local retrieval capability, some on-board image processing and display faculty, effective for allowing exhibition, is required. Alternatively, the stored information may be downloaded to another device for display thereon. For example, the image capturing device may be coupled by a universal serial bus (USB) connector or other suitable wire based and/or wireless interconnection modality to a personal computer (PC), notebook computer, or personal digital assistant (PDA). The stored information may then be downloaded thereto, processed, and displayed accordingly.
Conventional portable image capturing devices for printed media are typified by two main configurations, at opposite extremes of complexity. At the simple end are inexpensive line-of-text scanners, some appearing similar to a somewhat oversized pen or highlighter type writing implement. Line-of-text scanners are very simple devices of relatively low capability. They are utilized by running an optical acquisition portal over a line of text to be captured. They typically capture a line or a few lines of text. However, the captured textual line snippets captured therein may not easily be stitched back together. Thus their application for all but the most rudimentary scanning tasks is quite limited.
At the opposite end are a genus of rather complex, more capable conventional portable scanning systems, capable of significantly more complicated scanning tasks. Thus, they are substantially more useful. For example, conventional portable scanners may be used to capture whole pages of text. In as much as their portability demands a small size to ensure ease of handling and use, conventional portable scanner systems are typically smaller than the pages of most common books or document sizes; on the order of three by six inches (3″×6″).
To effectively scan a full sized document pages therefore, such as an 8½″×11″, 8½″×14″, A4, etc., and/or various book sizes, such as 4⅞″×7 5/16″, 5¾″×8⅞″, etc., the optical acquisition portal of the portable scanner system is passed over the pages, individually, in a number of swath passes, until the entire page, or as much of the text thereon as is desired, is covered by the scanning. The portable scanning system incorporates an on-board capability to stitch the individually scanned swaths of text together into an electronic format duplicating their on-page layout.
Typically, the capability to stitch together the individually scanned textual swaths is effectuated by a separate on-board navigational system. In fact, some conventional navigational systems apply two separate optical scanning systems that take very rapid snapshots of the page being scanned. These actually track the grid-like layout of paper fibers constituting the physical makeup of the page. This functionality is simultaneous with a separate, third, ink-based textual optical scan and recordation functionality. The dual navigational scan system scans and records the resulting on-page fiber grid geography mnemonically, and implements an algorithm correlating the information from the two navigational scans into a positional reference. Further, the dual navigational scan system implements an algorithm correlating the textual information captured by the separate text scan with the positional reference. In this manner, conventional portable scanners attempt to effectuate a stitch-together reconstruction of the macro-layout of the text.
In a number of areas, the conventional art is problematic. One problem is that conventional portable scanners are fairly complex systems for their size and intended application. Like other systems of undesirably high complexity, conventional portable scanners are somewhat expensive and prone to failures. For example, the conventional portable scanners have the three separate scanning features discussed above; two of them navigational and one textual. Obviously, this tripling of scanning requirements increases cost. In fact, the conventional navigational scan system, concentrating as it does on the fiber grid constituting the physical page construction, is not naturally in simpatico with the ink-based text capturing scan system, and vice versa.
Designing the text stitch-together functionality around these scan system disharmonies increases its own costs, also. Not only must both navigational systems be in perfect synchronism and alignment with each other, but the third text gathering scanning system must also be perfectly synchronized and aligned with both navigational systems. This need for calibrated, precision alignment increases manufacturing costs, especially those due to quality assurance and calibration. Correspondingly higher unit prices reflect this.
Another difficulty with the conventional art is inherent in the navigational system itself. When contact-requiring portable scanners lose contact with the page being scanned, such as due to tilting or lifting from the page surface, or if they run off the end of the page, information is lost. The entire scan in progress when contact is broken must be repeated, because the navigational system loses positional reference with which the text was to be stitched together. To users struggling to gather information in the portable milieu, which may often be far less comfortable, safe, and/or relaxed than desirable, this is wasteful, time-consuming, repetitive, and costly.
Further, this precision alignment is especially vulnerable to becoming misaligned in these portable systems, owing to the relatively rugged attributes accompanying portability itself, as well as to the manner in which the portable scanners are used. Movement and mechanical shock and vibration are common attributes of the operational milieu of portable systems in general. These tend to missallign precision optics such as the three separate scan systems of conventional portable scanners. Further still, the physical design and manner of use of conventional portable scanning systems exacerbates this problem.
Focal lengths and other optical parameters of conventional portable scanners, as well as application of CIS devices in lieu of CCDs therein requires, first, that such devices be used with an optical portal in contact with the page being scanned. Environmental conditions, such as curvature of the pages of a book being scanned, irregularities in the surface upon which a document is laid for scanning, and conditions related to movement, such as vibration, pitch, yaw, and roll, acceleration and jerkiness may interfere with or preclude this requirement for scanning surface flatness. The first of these factors is, of course, shared in common with stationary scanners. The rest of the factors, however, are unique to portable scanners.
Some conventional portable scanners are somewhat long and correspondingly top-heavy to achieve their requisite focal lengths. This is cumbersome and awkward, and tends to amplify the negative effects of surface and movement on the scanning process. Top-heavy portable scanners are difficult to control in some applications, and especially to keep in contact with the page being scanned.
One problem of the conventional art may aggravate the problems of loss of information. The user may not be aware that optical contact was broken, terminating a particular scan swath and requiring its repetition. This can be especially vexing, requiring repetition of the entire scan from start to finish, if it goes undetected until the end of a scan effort.
Another problem is that existing systems have limited format capabilities. Conventional portable scanners only posses contact image gathering capability; they do not take photographs of real world images. Conversely, digital cameras, while they may photograph a page of text like any other object, are not optimized for gathering textual information. Users of both devices encounter situations wherein both types of information must be captured. For example, an architect or a construction engineer may employ a portable scanner to gather the information contained in a job-site specification, and a digital camera to photograph scenes of construction in progress (or videotape construction activity) at the job site. For each information gathering task, the user must have one of each type of conventional image capturing devices at hand. This is cumbersome, duplicative, wasteful, and costly.
However, combining both functions into a single device has been conventionally impractical, because the optical systems required for each separate function are inapposite to those required for the other. Cameras (still and video) usually require optical systems that either focus over a range from close-in to infinity, or have a fixed focus of near infinity. Their ability to capture textual images and data are limited by optical distortions, including barrel distortion, limited or lacking illumination and difficulties in illuminary control, and depth of focus constraints. Portable scanners, on the other hand, require the essentially point-blank optical contact discussed above.
What is needed is a compact, portable system for capturing both two dimensional and three dimensional images from printed and related media. What is also needed is a compact, portable system for capturing both two dimensional and three dimensional images from printed and related media, as well as scenic images, such as photographs and/or video, combining the optical features of scanning and photography. Further, what is needed is such a system that is relatively simple and inexpensive, and which is easy to operate, rugged, reliable, and not unduly prone to optical misalignment, or cessation of scanning with loss of information, requiring repetition of scanning efforts. Further still, what is needed is a compact, portable system for capturing both two dimensional and three dimensional images from printed and related media, as well as scenic images, such as photographs and/or video, and which provides constant user feedback of the scan quality and effectiveness, during the scan process. Yet further still, what is needed is a system that accomplishes the foregoing and integrates the navigational and text-gathering functionalities seamlessly, transparently, and reliably.